Question

$\mathfrak \blue{ Question }$
$\sf{ Answer \: the \: following }$

(α) What is the difference between gravitational potential energy and elastic energy? give one example of a body having gravitational potential energy and another having elastic potential energy.

(b) If 784 J of work was done in lifting a 20 kg mass, calculate the height through which it was lifted. (g=9.8m/s²)​

Answer 1

Answers:

Part (a)

First, we can understand the meaning of the terms gravitational potential energy and elastic energy.

⇒ Gravitational potential energy:

The potential energy acquired by a body due to its height above from the ground is known as gravitational potential energy.

Formula: U = mgh [mass x gravitational field x height]

⇒ Elastic energy:

The release of the potential energy stored in an elastic object due to a force applied is known as elastic energy.

Formula: $\sf{U=\dfrac{1}{2}kx^2}$

Now, we can find the difference between both the type of energies with an example each:

DIFFERENCES:

✳ Gravitational potential energy is caused by the gravitational force while the elastic energy is caused by the elasticity of the object, that is, the electrostatic forces present between the molecules of the object.

✳ Gravitational potential energy only occurs when the object is placed above the ground while in elastic energy, the only thing that is needed is force to change the shape of the object.

✳ Example of gravitational potential energy: The energy in the river water before it falls down a waterfall.

✳ Example of elastic energy: Stretching of a rubber band.

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Part (b)

⇒ Given:

Work done, U = 784 J

Mass, m = 20 kg

Acceleration due to gravity = 9.8 m/s²

⇒ To Find:

The height to which the weight was lifted.

⇒ Formula to be used:

→ $\boxed{\sf{U=mgh}}$

⇒ Solution:

We know that:

→ Work done is 784 J

→ Mass of the object is 20 kg

→ Acceleration due to gravity is 9.8 m/s²

What we need to find is the height to which the object was lifted.

Here, we can use the formula:

U = mgh

Substituting the values we have in the equation:

$\sf{784=20\times9.8\times\:h}$

$\sf{784=196\times\:h}$

$\sf{h=\dfrac{784}{196}}$

$\sf{h=4\:m}$

Hence the height to which the weight was lifted is 4 m.

Answer 2

$Answers:</p><p></p><p>Part (a)</p><p>First, we can understand the meaning of the terms gravitational potential energy and elastic energy.</p><p>⇒ Gravitational potential energy:</p><p>The potential energy acquired by a body due to its height above from the ground is known as gravitational potential energy.</p><p>Formula: U = mgh [mass x gravitational field x height]</p><p>⇒ Elastic energy:</p><p>The release of the potential energy stored in an elastic object due to a force applied is known as elastic energy.</p><p>Formula: \sf{U=\dfrac{1}{2}kx^2}U=21kx2</p><p>Now, we can find the difference between both the type of energies with an example each:</p><p>DIFFERENCES:</p><p>✳ Gravitational potential energy is caused by the gravitational force while the elastic energy is caused by the elasticity of the object, that is, the electrostatic forces present between the molecules of the object.</p><p>✳ Gravitational potential energy only occurs when the object is placed above the ground while in elastic energy, the only thing that is needed is force to change the shape of the object.</p><p>✳ Example of gravitational potential energy: The energy in the river water before it falls down a waterfall.</p><p>✳ Example of elastic energy: Stretching of a rubber band.</p><p>━━━━━━━━━━━━━━━━━━━</p><p>Part (b)</p><p>⇒ Given:</p><p>Work done, U = 784 J</p><p>Mass, m = 20 kg</p><p>Acceleration due to gravity = 9.8 m/s²</p><p>⇒ To Find:</p><p>The height to which the weight was lifted.</p><p>⇒ Formula to be used:</p><p>→ \boxed{\sf{U=mgh}}U=mgh</p><p>⇒ Solution:</p><p>We know that:</p><p>→ Work done is 784 J</p><p>→ Mass of the object is 20 kg</p><p>→ Acceleration due to gravity is 9.8 m/s²</p><p>What we need to find is the height to which the object was lifted.</p><p>Here, we can use the formula:</p><p>U = mgh</p><p>Substituting the values we have in the equation:</p><p>\sf{784=20\times9.8\times\:h}784=20×9.8×h</p><p>\sf{784=196\times\:h}784=196×h</p><p>\sf{h=\dfrac{784}{196}}h=196784</p><p>\sf{h=4\:m}h=4m</p><p>Hence the height to which the weight was lifted is 4 m.</p><p>$